Time-controlled electric switch



Nov; 1 1, 1941.

- H. C.- M. STEVENS TIME-CONTROLLED ELECTRIC SWITCH Filed Nov. 12, 1940 2 Sheets-Sheet 1 'j Mame I zf .ZZ/Eer/A 62 x752 DVSULAT/OA/ $149055" Wuzw J TIME-CONTROLLED ELECTRIC SWITCH Filed Nov. 12, 1940 2 Sheets-Sheet 2 H. c. M. STEVENS 2,262,122

Patented Nov. 11, 1941 TIME-CONTROLLED ELECTRIC SWITCH Herbert Charles Macleod Stevens, Bradford-on- Tone, England Application November 12, 1940, Serial No. 365,365

In Great Britain March 8, 1939 2 Claims.

This invention relates to time-controlled electric switches adapted for use in conjunction with inertia starters for internal combustion engines, the starters being of the kind in which energy from an electric motor is stored in a fly wheel and in which after the fly wheel has been rotated an electrically controlled clutch element on the starter is connected with a complementary element on the engine.

It is known to use a hand operated switch for controlling the circuit containing the motor (herein termed the motor circuit) and the circuit containing an electrically operated clutch engaging means (herein termed the clutch circuit), the period during which the motor circuit is allowed to remain closed being determined by a time-mechanism, and the subsequent closing of the clutch circuit being effected by an additional hand movement.

An object of the present invention is to provide an improved switch whereby the closing of the two circuits in proper sequence and for appropriate time intervals can be efiected in a simple and convenient manner.

The invention comprises the combination with a switch (with any convenient time-mechanism) for controlling the motor circuit and operable by a hand lever, of a spring loaded lever carrying a contact for controlling the clutch circuit, a spring loaded catch for engaging this lever, and a cam with a complementary contact connected to the hand lever of the motor-circuit switch, the arrangement being such that the first mentioned contact is brought into and moved out of the path of the other contact under the control of the cam at appropriate stages in the action of the mechanism.

In the accompanying explanatory drawings:

Figure l is a diagram illustrating a system including an inertia starter and switch mechanism in accordance with the invention.

Figure 2 is an elevation of a part of the switch mechanism shown in Figure 1.

Figure 3 is an elevational view of parts of the switch mechanism illustrating the positions of the cam and levers after the shaft has been manually rotated.

Figure 4 is a similar view illustrating the manner in which the contacts are engaged immediately prior to retracted movement of the contact carrying lever.

Figure 5 is an enlarged diagrammatic view of the manually operable switch.

In Figure 1 the inertia starter is indicated by a and contains a fly wheel (not shown) which after being rotated by an electric motor b can be connected to an internal combustion engine by the engagement of a clutch element 0 on the starter with a complementary clutch element on the engine, the starter clutch element being movable axially into and out of engagement with the complementary clutch element under the control of an electromagnet d. A battery e for supplying current to the motor I) and the electromagnet d is arranged in the motor circuit f, and also in a circuit g containing the electromagnet, the latter circuit being herein termed the clutch circuit, and the two circuits being controlled by a switch mechanism forming the subject of the present invention.

In carrying the invention into effect as shown in Figures 1 and 2, I employ any convenient switch having a contact h which is movable relatively to a complementary fixed contact 1' by a spring loaded hand lever k for controlling the motor circuit 1, and which has combined with it any convenient time-mechanism such as a rotary air-vane ID as shown in Fig. 5 for controlling the rate of return of the lever it when released and hence the duration of time for which the switch remains closed. This switch is connected across the battery e and when closed enables current from the battery to energise an electromagnet m for closing the motor circuit f. The hand lever and switch contact hare mounted on a rotatable shaft n which also carries, coaxially with the hand lever, a cam 0 provided with or having a part 10 adapted to serve as one of the contacts for controlling the clutch circuit g. Adjacent to and operable by the cam o is a second lever q which carries the other of the contacts 1- for controlling the clutch circuit 9, and which is arranged in the same plane as a third lever s also operable by the cam. Normally the third lever s serves as a catch for holding the contact carrying lever q in a position in which its contact 1' lies out of the path of the contact 10 on the cam o as shown in Figure 2, and for this purpose the catch lever s is provided near its outer end with an inclined shoulder t for engaging a complementary surface u on the outer end of the contact carrying lever q. The latter lever q and the catch lever s are interconnected and loaded by a tension spring 1) which, when the catch lever s is released from the contact carrying lever q by the interaction of a nose w on the cam o with a projection a: on the catch lever, serves to move the contact carrying lever into a position in which its contact r lies in the path of the contact p on the cam, as

shown in Fig. 3. Such inward movement of the contact carrying lever q is terminated by the engagement of the inclined surface it on its outer end with another inclined shoulder g on the catch lever. The tension spring u also serves, by its action on the catch lever s, to return the contact carrying lever q quickly to its initial outer position upon the lever q being first caused by the interaction of its contact 1' with the cam to assume a position shown in Fig. 4 in which its inclined end surface u can be re-engaged by the first mentioned inclined shoulder 15 on th catch lever. This guide movement of the lever 3 effects the required rapid interruption of the circuit through the contacts r, p.

The arrangement of the parts above described and the shape of the cam o are such that during the closing movement of the motor switch contact h by the hand lever is the cam 0 moves the catch lever out of engagement with the contact carrying lever q, and the latter is moved by the tension spring 1; into a position in which its contact 1" lies in the path of the contact on the cam, as indicated in Figure 3. After the hand lever 70 has been released it returns under the action of its spring l2 at a rate controlled by the time mechanism Ill, and after a predetermined interval of time the motor switch h, i reopens. Meanwhile the cam 0, which is also returning with the hand lever 70, causes its contact p to approach its complementary contact r on the lever q. But these two contacts 11, 1 do not engage until a predetermined time after the opening of the motor switch h, 1'. When the two contacts p, r engage the clutch circuit g is closed and remains closed until the contact on the cam, by its action on the complementary contact r causes the contact carrying lever q to assume the position shown in Fig. 4 in which its inclined end surface it can be re-engaged by the first mentioned inclined shoulder 75 on the catch lever s, whereupon the lever s is caused by its loading spring u to move the contact carrying lever q with its contact to its initial outer position clear of the contact on the cam. In one convenient cycle of action, the motor circuit I after closing remains closed for about ten seconds. After this period an interval of about one second occurs before the clutch circuit g is closed, and this remains closed for about two seconds before the switch hand lever it reaches its initial position.

For enabling the switch mechanism to bring into action the starter of either of a pair of engines, I may duplicate the parts p to y and arrange the two sets of such parts at opposite sides of the cam o as shown in Figure 2. In this case the fixed contact 2' of the switch operable with the cam o by the hand lever k is also duplicated as. shown in Fig. 5, the arrangement being such circuit to be closed if and when required in special circumstances independently of the other switch p, 1. Also in parallel with the clutch circuit may be provided a warning light 3 to give an indication when this circuit is closed.

The invention, insofar as it relates to the switch above described for controlling the motor and clutch circuits of the starter, is not limited to the example described, as subordinate mechanical or constructional details may be varied to suit different requirement.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A switch mechanism for use in conjunction with an inertia starter of the type described comprising in combination, a motor circuit, a time switch for controlling the motor circuit, a hand lever for actuating said switch, a clutch circuit, a spring biased lever, a contact carried by the spring biased lever connected to the clutch circuit, a spring biased catch for engaging the spring biased lever, and a cam having a contact thereon connected to the clutch circuit rotated by the hand lever whereby the first contact is moved into and out of the path of the other contact under the control of the'cam at appropriate stages in the action of the mechanism.

2. A switch mechanism for use in conjunction with an inertia starter of the type'described comprising in combination, a motor circuit, a time switch for closing and opening the motor circuit, a clutch circuit, a cam rotated by the time switch, a contact on the cam connected to the clutch circuit, a first pivotable lever, a contact carried by said lever connected to the clutch circuit, a second lever pivotable by said cam normally holding the first lever with the contact thereof out of the path of movement of the cam contact, a spring biasing said first lever after release thereof by the second lever to a position with the contact thereof in the path of movement of the cam contact whereby the first lever is pivoted by the cam, and means carried by the second lever for moving the first lever with the contact thereof away from the cam contact after a preliminary pivoting of the first lever by the cam.

HERBERT CHARLES MACLEOD STEVENS. 

